package plugins

import (
	"encoding/json"
	"fmt"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

	"agent-system-backend/internal/skills"
	"agent-system-backend/internal/store"
	"agent-system-backend/internal/tools"
	core "agent-system-core"
)

func (h *Host) SetSkillsRoot(dir string) { h.skillsRoot = dir }

func (h *Host) SetHostAPI(baseURL, token string) {
	h.hostAPI, h.hostToken = baseURL, token
}

func (h *Host) startSidecar(m core.PluginManifest, dir string) error {
	if m.Backend.Mode != "sidecar" || m.Backend.Command == "" {
		return nil
	}
	cmdPath := m.Backend.Command
	if !filepath.IsAbs(cmdPath) {
		if _, err := os.Stat(filepath.Join(dir, cmdPath)); err == nil {
			cmdPath = filepath.Join(dir, cmdPath)
		}
	}
	cmd := exec.Command(cmdPath, m.Backend.Args...)
	cmd.Dir = dir
	cmd.Env = append(os.Environ(),
		"AGENT_HOST_API="+h.hostAPI,
		"AGENT_HOST_TOKEN="+h.hostToken,
		"AGENT_PLUGIN_ID="+m.ID,
	)
	if err := cmd.Start(); err != nil {
		return fmt.Errorf("plugins: %s: sidecar: %w", m.ID, err)
	}
	h.mu.Lock()
	if h.sidecars == nil {
		h.sidecars = map[string]*exec.Cmd{}
	}
	if prev := h.sidecars[m.ID]; prev != nil && prev.Process != nil {
		_ = prev.Process.Kill()
	}
	h.sidecars[m.ID] = cmd
	h.mu.Unlock()
	go func() { _ = cmd.Wait() }()
	return nil
}

func (h *Host) loadDeclared(dir string, m core.PluginManifest, ld *Loaded) error {
	for _, name := range m.Provides.Skills {
		body, err := os.ReadFile(filepath.Join(dir, "skills", name+".md"))
		if err != nil {
			return fmt.Errorf("plugins: %s: skill %s: %w", m.ID, name, err)
		}
		// 技能按开放规范校验（N2 WP4）：不合规整批拒载，字段定位到键。
		if err := skills.ValidateForPlugin(m.ID, name, body); err != nil {
			return err
		}
		if ld.Skills == nil {
			ld.Skills = map[string]string{}
		}
		ld.Skills[name] = string(body)
		if h.skillsRoot != "" {
			dest := filepath.Join(h.skillsRoot, "plugin-"+m.ID, name)
			if err := os.MkdirAll(dest, 0o755); err != nil {
				return err
			}
			if err := os.WriteFile(filepath.Join(dest, "SKILL.md"), body, 0o644); err != nil {
				return err
			}
		}
	}
	for _, name := range m.Provides.MCPServers {
		var srv core.PluginMCPServer
		if err := readAsset(dir, "mcp", name, &srv); err != nil {
			return fmt.Errorf("plugins: %s: mcp %s: %w", m.ID, name, err)
		}
		if srv.Name == "" {
			srv.Name = name
		}
		ld.MCP = append(ld.MCP, srv)
	}
	for _, name := range m.Provides.Knowledge {
		var item core.PluginKnowledgeSet
		if err := readAsset(dir, "knowledge", name, &item); err != nil {
			return fmt.Errorf("plugins: %s: knowledge %s: %w", m.ID, name, err)
		}
		ld.Knowledge = append(ld.Knowledge, item)
	}
	for _, name := range m.Provides.Parsers {
		var item core.PluginParserDecl
		if err := readAsset(dir, "parsers", name, &item); err != nil {
			return fmt.Errorf("plugins: %s: parser %s: %w", m.ID, name, err)
		}
		ld.Parsers = append(ld.Parsers, item)
	}
	for _, name := range m.Provides.Agents {
		raw, err := readPluginFile(dir, filepath.Join("agents", name+".json"))
		if err != nil {
			return fmt.Errorf("plugins: %s: agent %s: %w", m.ID, name, err)
		}
		item, err := parseAgentAsset(raw)
		if err != nil {
			return fmt.Errorf("plugins: %s: agent %s: %w", m.ID, name, err)
		}
		ld.Agents = append(ld.Agents, item)
	}
	for _, name := range m.Provides.Channels {
		var item core.PluginChannelDecl
		if err := readAsset(dir, "channels", name, &item); err != nil {
			return fmt.Errorf("plugins: %s: channel %s: %w", m.ID, name, err)
		}
		ld.Channels = append(ld.Channels, item)
	}
	for _, name := range m.Provides.Pages {
		var item core.PluginPageDecl
		if err := readAsset(dir, "pages", name, &item); err != nil {
			return fmt.Errorf("plugins: %s: page %s: %w", m.ID, name, err)
		}
		if item.Module == "" {
			return fmt.Errorf("plugins: %s: page %s: missing module", m.ID, name)
		}
		ld.Pages = append(ld.Pages, item)
	}
	if m.Backend.SchemaVersion > 0 && h.st != nil {
		cur, err := h.st.PluginSchemaVersion(m.ID)
		if err != nil {
			return err
		}
		if m.Backend.SchemaVersion < cur {
			return fmt.Errorf("plugins: %s: schema %d older than stored %d", m.ID, m.Backend.SchemaVersion, cur)
		}
		if err := h.st.SetPluginSchemaVersion(m.ID, m.Backend.SchemaVersion); err != nil {
			return err
		}
	}
	return nil
}

// MCPServers 返回已装载插件贡献的 MCP 服务，供与 settings 合并。
func (h *Host) MCPServers() []core.PluginMCPServer {
	h.mu.RLock()
	defer h.mu.RUnlock()
	var out []core.PluginMCPServer
	for _, ld := range h.loaded {
		out = append(out, ld.MCP...)
	}
	return out
}

// ListFor 按租户授权与 manifest 作用域过滤。project 为空时只检查租户。
func (h *Host) ListFor(owner, project string) []*Loaded {
	all := h.List()
	var out []*Loaded
	for _, ld := range all {
		if !ld.Manifest.Scope.Allows(owner, project) {
			continue
		}
		if h.st != nil && owner != "" {
			on, err := h.st.PluginEnabled(owner, ld.Manifest.ID)
			if err != nil || !on {
				continue
			}
		}
		out = append(out, ld)
	}
	return out
}

func (h *Host) bindToolExecutor(desc core.ToolDesc, apiVersion string, allow []string) (tools.Executor, error) {
	if desc.HTTP == nil {
		return nil, fmt.Errorf("v1 仅支持声明式 HTTP 工具（缺少 http 段）")
	}
	if desc.HTTP.URL == "" || desc.HTTP.Method == "" {
		return nil, fmt.Errorf("http 工具缺少 url/method")
	}
	if err := checkNetwork(apiVersion, allow, desc.HTTP.URL); err != nil {
		return nil, err
	}
	return func(rc tools.ToolExecCtx, args json.RawMessage) (string, error) {
		if err := checkNetwork(apiVersion, allow, desc.HTTP.URL); err != nil {
			return "", err
		}
		owner := store.OwnerDefault
		if rc != nil && rc.OwnerID() != "" {
			owner = rc.OwnerID()
		}
		lookup := func(key string) string {
			eff := h.settings.Effective(owner, "")
			if desc.PluginID != "" {
				if v := eff.GetString("secrets."+desc.PluginID+"."+key, ""); v != "" {
					return v
				}
			}
			return eff.GetString(key, "")
		}
		return tools.HTTPExecutor(*desc.HTTP, lookup)(rc, args)
	}, nil
}

func checkNetwork(apiVersion string, allow []string, rawURL string) error {
	if len(allow) == 0 {
		if apiVersion == core.PluginAPIVersionExperimental {
			return fmt.Errorf("plugins: api %s 要求 requires.network", apiVersion)
		}
		return nil
	}
	u, err := url.Parse(rawURL)
	if err != nil {
		return fmt.Errorf("plugins: tool url: %w", err)
	}
	host := u.Hostname()
	for _, a := range allow {
		a = strings.TrimPrefix(strings.ToLower(strings.TrimSpace(a)), "*.")
		h := strings.ToLower(host)
		if h == a || strings.HasSuffix(h, "."+a) {
			return nil
		}
	}
	return fmt.Errorf("plugins: host %s not in network allowlist", host)
}